diff --git a/tests/migrate-date-format.expected b/tests/migrate-date-format.expected
index 8ba89fa..8648a03 100644
--- a/tests/migrate-date-format.expected
+++ b/tests/migrate-date-format.expected
@@ -1,17 +1,16 @@
 + adr init
 doc/adr/0001-record-architecture-decisions.md
+++ ADR_DATE=12/01/1992
 ++ adr new With Old Date Format
 + adr_file=doc/adr/0002-with-old-date-format.md
-+ sed -e 's+^Date: .*$+Date: 12/01/1992+' doc/adr/0002-with-old-date-format.md
-+ mv doc/adr/0002-with-old-date-format.md.tmp doc/adr/0002-with-old-date-format.md
 + adr new With Current Date Format
 doc/adr/0003-with-current-date-format.md
-+ grep 'Date: ' doc/adr/0001-record-architecture-decisions.md doc/adr/0002-with-old-date-format.md doc/adr/0003-with-current-date-format.md
++ grep Date: doc/adr/0001-record-architecture-decisions.md doc/adr/0002-with-old-date-format.md doc/adr/0003-with-current-date-format.md
 doc/adr/0001-record-architecture-decisions.md:Date: 1992-01-12
 doc/adr/0002-with-old-date-format.md:Date: 12/01/1992
 doc/adr/0003-with-current-date-format.md:Date: 1992-01-12
 + adr upgrade-repository
-+ grep 'Date: ' doc/adr/0001-record-architecture-decisions.md doc/adr/0002-with-old-date-format.md doc/adr/0003-with-current-date-format.md
++ grep Date: doc/adr/0001-record-architecture-decisions.md doc/adr/0002-with-old-date-format.md doc/adr/0003-with-current-date-format.md
 doc/adr/0001-record-architecture-decisions.md:Date: 1992-01-12
 doc/adr/0002-with-old-date-format.md:Date: 1992-01-12
 doc/adr/0003-with-current-date-format.md:Date: 1992-01-12
diff --git a/tests/migrate-date-format.sh b/tests/migrate-date-format.sh
index 18e1ef3..5039f17 100644
--- a/tests/migrate-date-format.sh
+++ b/tests/migrate-date-format.sh
@@ -1,8 +1,6 @@
 adr init
-adr_file="`adr new With Old Date Format`"
-sed -e 's+^Date: .*$+Date: 12/01/1992+' "$adr_file" > "$adr_file.tmp"
-mv "$adr_file.tmp" "$adr_file"
+adr_file="$(ADR_DATE=12/01/1992 adr new With Old Date Format)"
 adr new With Current Date Format
-grep 'Date: ' doc/adr/*
+grep Date: doc/adr/*
 adr upgrade-repository
-grep 'Date: ' doc/adr/*
+grep Date: doc/adr/*